Expandable lng processing plant

ABSTRACT

An LNG processing plant positioned at a processing location adjacent to a body of water is described. The LNG processing plant includes A) a first phase LNG processing plant for processing an initial plant capacity of LNG, the first phase LNG processing plant including a plurality of first phase facilities, each first phase facility provided with plant equipment related to a pre-determined function associated with the processing of LNG, wherein one or more of the plurality of first phase facilities is arranged on a deck of a structure wherein the deck is arranged above the level of the water at a selected offshore or near-shore location; and, B) one or more second phase facilities provided on the deck of the structure to provide a second phase LNG processing plant, said second phase LNG processing plant having a maximum plant capacity that is higher than the initial plant capacity.

FIELD OF THE INVENTION

The present invention relates to an expandable liquefied natural gas(LNG) processing plant. More particularly, some embodiments of theinvention are related to LNG production plants. Other embodiments of theinvention are related to natural gas regasification plants.

BACKGROUND TO THE INVENTION

Large volumes of natural gas (i.e., primarily methane) are located inremote areas of the world. This gas has significant value if it can beeconomically transported to market. Natural gas (“NG”) is routinelytransported from an onshore LNG production plant to another location inits liquid state as liquefied natural gas (“LNG”) by way of loading theLNG in the cryogenic storage tanks of purpose built large ocean goingvessels known as “LNG Carriers”. Liquefaction of the natural gas makesit more economical to transport as LNG occupies only about 1/600th ofthe volume than the same amount of natural gas does in its gaseousstate. Prior to liquefaction, raw natural gas that has been sourced froma wellhead is subjected to a series of gas pre-treatment processesincluding acid gas removal and dehydration to remove contaminants. Afterliquefaction, LNG is typically stored in cryogenic storage tanks at theLNG production plant either at or slightly above atmospheric pressure ata temperature of around −160 degrees Celsius.

Gas pre-treatment, liquefaction and storage are typically undertaken ata fixed onshore LNG production plant associated with a jetty that isbuilt in sufficiently deepwater to allow berthing of the LNG Carriers. Atypical LNG Carrier can be 300 m long with a draft of 15 to 20 meters.The docking of such LNG Carriers requires special conditions of waterdepth and sea state. In some countries, it is necessary to construct apipeline and jetty several kilometers offshore to locate water that isdeep enough to allow the approach of an LNG Carrier. The costsassociated with the construction and installation of a jetty to allowberthing of an LNG Carrier is a major cost. To ship liquefied naturalgas (LNG) by sea, a way to transfer LNG between the cryogenic storagetanks of the onshore LNG production plant and the cryogenic storagetanks of the LNG Carrier is required. Traditionally, the transfer meanshas taken the form of an insulated pipe that is laid on an elevatedsupporting trestle structure between the onshore LNG production plantand the jetty so that the insulated pipe remains at all times above thewater line. These prior art transfer facilities include a vapour returnline to return boil-off gas to the onshore LNG production plant. AfterLNG have been loaded into the cryogenic storage tanks of the LNG Carriervessel for marine transport LNG is regasified before distribution to endusers through a pipeline or other distribution network at a temperatureand pressure that meets the delivery requirements of the end users.

The cost of traditional onshore LNG storage and offloading facilitieshas continued to increase through the years and is now a verysignificant component of the total installed cost for an LNG project.Efforts to reduce this cost have largely been focused on storage tanksize optimization and seeking to leverage the economics of scale viaincreased LNG train capacity size and improvement in LNG berthutilization. To avoid the costs associated with the construction of aport to service an onshore LNG production facility, it has been proposedto produce LNG at sea. In this context, the entire LNG production isperformed on a floating LNG production vessel. Alternatively, it hasbeen proposed to conduct gas pre-treatment onshore with liquefactionconducted offshore on a floating vessel with equipment optimized interms of size and layout to keep deck size to a minimum. Such gaspre-treatment includes the removal of water, sour gas species (CO₂ andH₂S) and heavy hydrocarbons. The pre-treated gas is then sent bypipeline to the floating liquefaction facility. Given their size andcomplexity, the costs associated with the implementation of a completeLNG liquefaction plant at sea are extremely high.

Onshore plants used to liquefy natural gas are typically built in stagesas the supply of feed gas, i.e. natural gas, and the quantity of gascontracted for sale, increase. Each stage normally consists of aseparate, stand-alone unit, commonly called an ‘LNG train’. An LNG traincomprises all of the individual components necessary to liquefy a streamof feed gas into LNG and send it on to a cryogenic storage tank. As thesupply of feed gas to the plant exceeds the capacity of one stand-aloneLNG train, additional stand-alone LNG trains are installed at theonshore plant, as needed, to handle increasing LNG production. Incontrast, the processing feed rate of an LNG plant onboard a floatingLNG production vessel, once constructed, cannot be altered, as allavailable deck space is utilised and optimised to keep the overall sizeof the floating LNG production vessel to a minimum.

The cost of LNG storage and offloading facilities has continued toincrease through the years and is now a very significant component ofthe total installed cost for an LNG project. Efforts to reduce this costhave largely been focused on storage tank size optimization and seekingto leverage the economics of scale via increased LNG train capacity sizeand improvement in LNG berth utilization.

There remains a need for an alternative LNG processing plant that mayaddress one or more of the above-described disadvantages of conventionalLNG processing plants.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is providedan LNG processing plant positioned at a processing location adjacent toa body of water, the LNG processing plant comprising:

-   -   A) a first phase LNG processing plant for processing an initial        plant capacity of LNG, the first phase LNG processing plant        comprising a plurality of first phase facilities, each first        phase facility provided with plant equipment related to a        pre-determined function associated with the processing of LNG,        wherein one or more of the plurality of first phase facilities        is arranged on a deck of a structure wherein the deck is        arranged above the level of the water at a selected offshore or        near-shore location; and,    -   B) one or more second phase facilities provided on the deck of        the structure to provide a second phase LNG processing plant,        said second phase LNG processing plant having a maximum plant        capacity that is higher than the initial plant capacity, wherein        the one or more second phase facilities are provided to expand        the plant capacity of the first phase LNG processing plant in        one or more incremental stages, and, the deck of the structure        is sized to provide a pre-allocated space for the installation        of the one or more second phase facilities on the deck of the        structure.

In one form, the one or more of the plurality of first phase facilitiesis arranged towards a first end of the deck with the pre-allocated spacebeing arranged towards a second opposite end of the deck. In one form,the one or more of the plurality of first phase facilities is arrangedtowards a first side of the deck with the pre-allocated space beingarranged towards a second opposite side of the deck.

In one form, the structure is a fixed structure or a floating structureor a gravity based structure having a base that rests on the seabed atthe selected location.

In one form, the structure includes a first cryogenic storage tank forreceiving and storing LNG. In one form, the first cryogenic storage tankis prismatic storage tank or a membrane storage tank. In one form, thefirst cryogenic storage tank is one of a plurality of first cryogenicstorage tanks. In one form, the first cryogenic storage tank has an LNGstorage capacity of at least 160,000 m³. In one form, the firstcryogenic storage tank has an LNG storage capacity in the range of160,000 m³ to 520,000 m³.

In one form, the structure has a length of up to 500 meters and a widthof up to 150 meters. In one form, the structure has a depth of up to 50metres.

In one form, the initial plant capacity of the first phase LNGprocessing plant is in the range of 0.5 to 7 million tons per annum ofLNG. In one form, the maximum plant capacity after expansion to providethe second phase LNG processing plant is in the range of 2 million to 50million tons per annum of LNG. In one form, one or more of the pluralityof first phase facilities is sized for processing both the initial plantcapacity and the maximum plant capacity.

In one form, one or more of second phase facilities is located on afixed platform, a semi-submersible or a jacket structure.

In one form, the one of more second phase facilities are modules havinga weight of greater than 7,000 tons. In one form, the modules have aweight of greater than 8,000 tons and up 100,000 tons.

In one form, the gravity structure includes one or both of a condensatestorage tank and an LPG storage tank.

In one form, the structure includes an LNG transfer facility for loadingLNG between from the first cryogenic storage tank of the structure to asecond cryogenic storage tank onboard an LNG Carrier, or for unloadingof LNG from the second cryogenic storage tank of an LNG Carrier to thefirst cryogenic storage tank of the structure.

In one form, the structure is constructed at a construction location andfloated in to the first processing location before being positioned atthe selected location. In one form, the structure is arranged to providea breakwater for an LNG Carrier at the selected location.

In one form, the structure is transportable from a first processinglocation to a second processing location. In one form, the structure isa gravity based structure and the gravity based structure includes aballast storage compartment arranged around the periphery of the gravitybased structure or arranged toward the base of the gravity basedstructure, for ballasting. In one form, the ballast storage compartmentis one of a plurality of ballast storage compartments.

In one form, the LNG processing plant is an LNG production plantarranged to receive a feed stream of natural gas and liquefy the naturalgas to produce a product stream of LNG.

In one form, the first phase LNG processing plant includes a first phasegas receiving facility for receiving a hydrocarbon stream comprisinghydrocarbon gas and liquids and separating the liquids, including one orboth of condensate and free water, from the hydrocarbon stream toproduce a hydrocarbon feed gas stream for a gas pre-treatment facility.In one form, the first phase gas receiving facility is arranged on thedeck of the structure. In one form, the first phase gas receivingfacility is arranged offshore or subsea. In one form, the first phasegas receiving facility is arranged onshore.

In one form, the first phase LNG processing plant includes a first phasegas pre-treatment facility for receiving a hydrocarbon feed gas streamfrom a gas receiving facility and removing contaminants from thehydrocarbon feed gas stream to produce a stream of pre-treated gas. Inone form, the first phase gas pre-treatment facility is arranged on thedeck of the structure. In one form, the first phase gas pre-treatmentfacility is arranged onshore. In one form, the first phase gaspre-treatment facility is arranged offshore. In one form, the firstphase LNG processing plant includes a first phase LNG liquefactionfacility for receiving the stream of pre-treated gas from a gaspre-treatment facility and liquefying the natural gas to produce aproduct stream of LNG.

In one form, the first phase LNG liquefaction facility is arranged onthe deck of the structure. In one form, the first phase LNG liquefactionfacility is arranged onshore. In one form, the first phase LNGliquefaction facility is arranged offshore. In one form, the structureincludes a boil-off gas reliquefaction facility for liquefying at leasta portion of the boil off gas that is generated in first cryogenicstorage tank.

In one form, the LNG processing plant is an LNG regasification plantarranged to receive a feed stream of LNG and vaporise the LNG to producea product stream of natural gas. In one form, the first phase LNGregasification plant includes a first phase power generation facilityfor generating a supply of power using a first phase product stream ofnatural gas as a source of fuel to generate electricity. In one form,the first phase power generation facility is arranged on the deck of thestructure. In one form, the first phase power generation facility isarranged offshore. In one form, the first phase power generationfacility is arranged onshore. In one form, the first phase powergeneration facility is a pre-existing onshore power plant.

In one form, the first phase LNG regasification plant includes a firstphase vaporised gas receiving facility arranged to receive a stream ofvaporised natural gas from a first phase regasification facility andsend out a first phase product stream of vaporised natural gas. In oneform, the first phase vaporised gas receiving facility is arranged onthe deck of the structure. In one form, the first phase vaporised gasreceiving facility is arranged offshore. In one form, first phasevaporised gas receiving facility is arranged onshore. In one form, thefirst phase LNG regasification plant includes a first phaseregasification facility arranged to vaporise a first phase feed streamof LNG to produce a first phase stream of vaporised natural gas which istransferred to a first phase vaporised gas receiving facility. In oneform, the first phase regasification facility is arranged on the deck ofthe structure. In one form, the first phase regasification facility isarranged offshore. In one form, the first phase regasification facilityis arranged onshore.

In one form, the initial plant capacity is at least 0.5 million tons peryear and the maximum feed processing capacity is at least 2 million tonsper year. In one form, the first initial plant capacity is at least 0.5million tons per year and the maximum feed processing capacity is notgreater than 50 million tons per year. In one form, the first initialplant capacity is at least 0.5 million tons per year and the maximumfeed processing capacity is not greater than 70 million tons per year.

According to a second aspect of the present invention there is provideda method of processing LNG in an LNG processing plant is positioned at aprocessing location adjacent to a body of water, the method comprising:

-   -   A) providing a first phase LNG processing plant for processing        an initial plant capacity of LNG, the first phase LNG processing        plant comprising a plurality of first phase facilities, each        first phase facility having plant equipment related to a        pre-determined function associated with the processing of LNG,        wherein one or more of the plurality of first phase facilities        is arranged on a deck of a structure, wherein the deck is        arranged above the level of the water at a selected offshore or        near-shore location; and,    -   B) expanding the plant capacity of the first phase LNG        processing plant in one or more incremental stages by providing        one or more second phase facilities on the deck of the structure        to provide a second phase LNG processing plant, said second        phase LNG processing plant having a maximum plant capacity that        is higher than the initial plant capacity, wherein the deck of        the structure is sized to provide a pre-allocated space for the        installation of the one or more second phase facilities on the        deck of the structure.

In one form, the step of processing LNG from the first phase LNGprocessing plant during step B). In one form, the step of arranging theone or more of the plurality of first phase facilities towards a firstend of the deck with the pre-allocated space being arranged towards asecond opposite end of the deck. In one form, the step of arranging theone or more of the plurality of first phase facilities towards a firstside of the deck with the pre-allocated space being arranged towards asecond opposite side of deck.

In one form, the initial plant capacity of the first phase LNGprocessing plant is in the range of 0.5 to 7 million tons per annum ofLNG. In one form, the maximum plant capacity after the step of expandingto the second phase LNG processing plant is in the range of 2 million to70 million tons per annum of LNG. In one form, the step of sizing theone or more of the plurality of first phase facilities for processingboth the initial plant capacity and the maximum plant capacity.

In one form, the step of locating one or more of second phase facilitiesis on a fixed platform, a semi-submersible or a jacket structure. In oneform, the method comprising providing the one or more second phasefacilities as modules having a weight of greater than 7,000 tons. In oneform, the modules have a weight of greater than 8,000 tons and up100,000 tons.

In one form, the method comprises the step of constructing the structureat a construction location and floating the structure into the firstprocessing location for positioning of the structure at the selectedlocation. In one form, the method comprises the step of arranging thestructure to provide a breakwater for an LNG Carrier at the selectedlocation. In one form, the method comprises the step of moving thestructure from a first processing location to a second processinglocation. In one form, the LNG processing plant is an LNG productionplant arranged to receive a feed stream of natural gas and liquefy thenatural gas to produce a product stream of LNG. In one form, the LNGprocessing plant is an LNG regasification plant arranged to receive afeed stream of LNG and vaporise the LNG to produce a product stream ofnatural gas.

In one form, the initial plant capacity is at least 0.5 million tons peryear and the maximum feed processing capacity is not greater than 50million tons per year. In one form, the initial plant capacity is atleast 2 million tons per year and the maximum feed processing capacityis not greater than 50 million tons per year.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate a more detailed understanding of the nature ofthe invention several embodiments of the present invention will now bedescribed in detail, by way of example only, with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic plan view of a first embodiment illustrating oneincremental stage of expansion of an LNG processing plant with the firstphase LNG processing plant shown in solid lines and the second phase LNGprocessing plant shown in dotted lines;

FIG. 2 is a schematic plan view of the first embodiment of an LNGprocessing plant with the first phase LNG processing plant shown insolid lines and the second phase LNG processing plant shown in solidlines;

FIG. 3 is a schematic side view of the first embodiment of an LNGprocessing plant illustrating a subsea pipeline extending from onshoreto a gravity based structure;

FIG. 4 is a schematic side view of the first embodiment of an LNGprocessing plant illustrating a trestle extending from onshore to agravity based structure;

FIG. 5 is a schematic representation of the structure being floated ortowed from a construction location or an assembly location to a firstprocessing location or being de-ballasted at a first processing locationand floated or towed to a second processing location for re-ballasting;

FIG. 6 is a schematic plan view of a second embodiment illustrating oneincremental stage of expansion of an LNG processing plant with the firstphase LNG processing plant shown in solid lines and the second phase LNGprocessing plant shown in dotted lines, with all facilities beingarranged on the deck of the structure;

FIG. 7 is a schematic plan view of the second embodiment of an LNGprocessing plant with the first phase LNG processing plant shown insolid lines and the second phase LNG processing plant shown in solidlines, with all facilities being arranged on the deck of the structure;

FIG. 8 is a schematic plan view of a third embodiment illustrating oneincremental stage of expansion of an LNG processing plant with the firstphase LNG processing plant shown in solid lines and the second phase LNGprocessing plant shown in dotted lines, with all of the facilitieslocated on the deck of the structure;

FIG. 9 is a schematic plan view of a third embodiment illustrating oneincremental stage of expansion of an LNG processing plant with the firstphase LNG processing plant shown in solid lines and the second phase LNGprocessing plant shown in dotted lines, with one of the facilitieslocated off the deck of the structure;

FIG. 10 is a schematic plan view of a third embodiment illustrating oneincremental stage of expansion of an LNG processing plant with the firstphase LNG processing plant shown in solid lines and the second phase LNGprocessing plant shown in dotted lines, with one of the facilitieslocated onshore;

FIG. 11 is a schematic plan view of a fourth embodiment illustrating oneincremental stage of expansion of an LNG processing plant with the firstphase LNG processing plant shown in solid lines and the second phase LNGprocessing plant shown in dotted lines, with all of the facilitieslocated on the deck of the structure;

FIG. 12 is a schematic plan view of a fourth embodiment illustrating oneincremental stage of expansion of an LNG processing plant with the firstphase LNG processing plant shown in solid lines and the second phase LNGprocessing plant shown in dotted lines, with one of the facilitieslocated off the deck of the structure;

FIG. 13 is a schematic plan view of a fourth embodiment illustrating oneincremental stage of expansion of an LNG processing plant with the firstphase LNG processing plant shown in solid lines and the second phase LNGprocessing plant shown in dotted lines, with one of the facilitieslocated onshore;

FIG. 14 is a schematic plan view of a fifth embodiment illustratingthree incremental stages of expansion of an LNG processing plant withthe first phase LNG processing plant shown in solid lines and the secondphase LNG processing plant shown in dotted lines;

FIG. 15 is a schematic plan view of the fifth embodiment of an LNGprocessing plant with the first phase LNG processing plant shown insolid lines and the second phase LNG processing plant shown in solidlines, after the addition of the first incremental stage;

FIG. 16 is a schematic plan view of the fifth embodiment of an LNGprocessing plant with the first phase LNG processing plant shown insolid lines and the second phase LNG processing plant shown in solidlines, after the addition of the first and second incremental stages;

FIG. 17 is a schematic plan view of the fifth embodiment of an LNGprocessing plant with the first phase LNG processing plant shown insolid lines and the second phase LNG processing plant shown in solidlines, after the addition of the first, second, and third and finalincremental stages;

FIG. 18 is a schematic plan view of a sixth embodiment illustratingthree incremental stages of expansion of an LNG processing plant byadding units or facilities installed on a fixed structure, with thefirst phase LNG processing plant shown in solid lines and the secondphase LNG processing plant shown in dotted lines;

FIG. 19 is a schematic plan view of the sixth embodiment of an LNGprocessing plant with the first phase LNG processing plant shown insolid lines and the second phase LNG processing plant shown in solidlines, after the addition of the first incremental stage;

FIG. 20 is a schematic plan view of the sixth embodiment of an LNGprocessing plant with the first phase LNG processing plant shown insolid lines and the second phase LNG processing plant shown in solidlines, after the addition of the first and second incremental stages;

FIG. 21 is a schematic plan view of the sixth embodiment of an LNGprocessing plant with the first phase LNG processing plant shown insolid lines and the second phase LNG processing plant shown in solidlines, after the addition of the first, second, and third and finalincremental stages;

FIG. 22 is a schematic side view of the sixth embodiment of an LNGprocessing plant illustrating a trestle extending from onshore to afloating structure; and,

FIG. 23 is a schematic side view of the sixth embodiment of an LNGprocessing plant illustrating a subsea pipeline extending from onshoreto a fixed structure.

It is to be noted that the drawings illustrate only preferredembodiments of the invention and are therefore not to be consideredlimiting of the invention's scope as it may admit to other equallyeffective embodiments. Like reference numerals refer to like parts. Thecomponents in the figures are not necessarily to scale, emphasis insteadbeing placed upon illustrating the principles of the invention.Moreover, all drawings are intended to convey concepts, where relativesizes, shapes and other detailed attributes may be illustratedschematically rather than literally or precisely.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

Particular embodiments of the present invention are now described. Theterminology used herein is for the purpose of describing particularembodiments only, and is not intended to limit the scope of the presentinvention. Unless defined otherwise, all technical and scientific termsused herein have the same meanings as commonly understood by one ofordinary skill in the art to which this invention belongs.

The acronym ‘LNG’ refers to liquefied natural gas. The acronym ‘LPG’refers to liquefied petroleum gas. The term ‘LNG Carrier’ refers to amarine transport vessel that is capable of carrying a cargo of liquefiednatural gas over water.

The term ‘onshore facility’ as used in this specification and in theclaims refers to a facility that is arranged entirely on land,preferably near a coastline.

The term ‘offshore facility’ as used in this specification and in theclaims refers to a facility that is arranged entirely in or over water,whereby the facility is surrounded by seawater in all directions. Theterm ‘near-shore facility’ as used in this specification and in theclaims refers to an offshore facility that is located in shallow water.The term ‘shallow water’ as used in this specification and in the claimsrefers to water that has a water depth of less than 50 m or less than 15m or less than 10 m or less than 5 m deep.

The distance between the onshore facility and the offshore facilitywhere there is a connecting pipeline may vary. This distance ispreferably greater than or equal to 5 km or greater than or equal to 10km, or greater than or equal to 15 km, or greater than or equal to 20km, or greater than or equal to 30 km or greater than or equal to 200km.

As used herein and in the claims the phrase ‘LNG processing plant’ meansany processing plant that produces a product that is changed in some wayfrom the feed, with the feed or the product being LNG. One example of aLNG processing plant is a LNG production plant for producing LNG.Another example of a LNG processing plant is a LNG vaporisation orregasification plant where the feed is LNG.

As used herein and in the claims the phrase ‘liquefaction facility’means a facility that processes a feed stream that includes gaseousmethane into a product stream that includes liquid methane. An LNGliquefaction plant includes at least one cryogenic heat exchanger and atleast one refrigerant compression system.

As used herein and in the claims, the phrase ‘gas pre-treatmentfacility’ means a facility that receives a feed stream which includes atleast methane, ethane, carbon dioxide, and hydrogen sulfide and producesa pre-treated gas stream which contains methane and reduced amounts ofthe other non-methane species as compared to the feed stream. The gaspre-treatment plant may include equipment for the removal of hydrogensulphide, carbon dioxide and water. The gas pre-treatment plant mayoptionally include equipment for the removal of mercury. The gaspre-treatment plant may include equipment for the removal of heavyhydrocarbons. The term ‘heavy hydrocarbon’ refers to a hydrocarboncompound with more than three carbon atoms in the chain.

Using the method and system of the present invention LNG is processed inan LNG processing plant is positioned at a processing location adjacentto a body of water, the method comprising:

-   -   A) providing a first phase LNG processing plant for processing        an initial plant capacity of LNG, the first phase LNG processing        plant comprising a plurality of first phase facilities, each        first phase facility having plant equipment related to a        pre-determined function associated with the processing of LNG,        wherein one or more of the plurality of first phase facilities        is arranged on a deck of a structure, wherein the deck is        arranged above the level of the water at a selected offshore or        near-shore location; and,    -   B) expanding the plant capacity of the first phase LNG        processing plant in one or more incremental stages by providing        one or more second phase facilities on the deck of the structure        to provide a second phase LNG processing plant, said second        phase LNG processing plant having a maximum plant capacity that        is higher than the initial plant capacity, wherein the deck of        the structure is sized to provide a pre-allocated space for the        installation of the one or more second phase facilities on the        deck of the structure.

In order to facilitate expansion, the deck of the structure is designedand sized to provide a pre-allocated space on the deck for theinstallation of the one or more second phase facilities on the deck.Advantageously, processing of LNG from the first phase LNG processingplant is able to continue during the step of expansion. The first phaseLNG processing plant is arranged on the deck of the structure in such away as to provide easy access to the pre-allocated space.

The LNG processing plant may be an LNG production plant arranged toreceive a feed stream of natural gas and liquefy the natural gas toproduce a product stream of LNG with reference to the first to the sixthembodiments of the present invention as described in detail below.Alternatively, the LNG processing plant may be a LNG regasificationplant arranged to receive a feed stream of LNG and produce and productstream of natural gas as described in detail below with reference to aseventh embodiment.

A first embodiment of the present invention is now described withreference to FIGS. 1 to 4 in the context of the LNG processing plantbeing an LNG production plant. More specifically, there is provided afirst phase LNG production plant for producing an initial plant capacityof LNG, the first phase LNG production plant comprising a plurality ofspaced-apart facilities, each facility provided with plant equipmentrelated to a pre-determined function associated with the liquefaction ofLNG. The first phase LNG production plant includes at least thefollowing facilities:

-   -   a) a gas receiving facility for receiving a hydrocarbon stream        comprising hydrocarbon gas and liquids and separating the        liquids, including one or both of condensate and free water,        from the hydrocarbon stream to produce a hydrocarbon feed gas        stream for a gas pre-treatment facility;    -   b) a gas pre-treatment facility for receiving a hydrocarbon feed        gas stream from the gas receiving facility and removing        contaminants from the hydrocarbon feed gas stream to produce a        stream of pre-treated gas;    -   c) a liquefaction facility for receiving the stream of        pre-treated gas from a gas pre-treatment facility and liquefying        the natural gas to produce a product stream of LNG;    -   d) a storage facility operatively associated with a transfer        means for receiving the product stream of LNG from the        liquefaction facility for receiving and storing LNG in a first        cryogenic storage tank; and,    -   e) an offloading facility including LNG transfer facilities to        transfer the LNG from the first cryogenic storage tank of the        storage facility to a second cryogenic storage tank onboard an        LNG Carrier on an as-needs basis.

Referring to FIGS. 1 to 4, an LNG processing plant 10, in the form of anLNG production plant, is positioned at a first processing location 12adjacent to a body of water 14. The LNG production plant 10 includes afirst phase LNG production plant 16 for producing an initial plantcapacity of LNG illustrated in solid lines in both FIG. 1 and FIG. 2,with a pre-allocated space provided on the deck of the structure for thelater expansion of the LNG processing plant 10 in one or moreincremental stages to provide a second phase LNG production plant 18,said second phase LNG production plant having a maximum plant capacitythat is higher than the initial plant capacity. The second phase LNGproduction plant 18 is illustrated in dotted lines in FIG. 1 and solidlines in FIG. 2. In the first embodiment illustrated in FIGS. 1 and 2,the plant capacity of the first phase LNG production plant 16 isincreased in one incremental stage by installing one or more secondphase facilities to provide the second phase production plant. Thisexpansion is able to be conducted without interruption to the processingof LNG by the first phase LNG production plant.

In the first embodiment now described with reference to FIGS. 1 to 4,the first phase LNG production plant 16 includes a first phase gasreceiving facility 20 (hereinafter referred to as a ‘slugcatcher’) forreceiving a hydrocarbon stream 21 comprising hydrocarbon gas and liquidsand separating the liquids, including one or both of condensate and freewater, from the hydrocarbon stream to produce a first phase hydrocarbonfeed gas stream 23. The LNG production plant 10 includes a first phaseoffshore gas pre-treatment facility 22 for producing a first phasestream of pre-treated gas 25. In this embodiment, the first phase LNGproduction plant 16 includes a first phase liquefaction facility 24 forreceiving the first phase stream of pre-treated gas 25 from the gaspre-treatment facility 22 and liquefying the first phase pre-treated gasstream 25 to produce a first phase product stream of LNG 26. The firstphase product stream of LNG is produced at a rate that is determined bythe initial plant capacity of LNG of the first phase LNG productionplant 16.

By way of example only, the initial plant capacity of the first phaseLNG production plant is in the range of 0.5 to 7 million tons per annumof LNG. The maximum plant capacity after expansion to provide the secondphase LNG production plant is in the range of 2 million to 50 milliontons per annum of LNG.

The first phase gas pre-treatment facility 22 includes equipment foracid gas removal, dehydration and, optionally, mercury removal and heavyhydrocarbon removal of the kind that is known in the art. Liquefactionis achieved in the first phase liquefaction facility 24 using anyliquefaction process well established in the art which typically involvecompression, expansion and cooling. Such prior art liquefactionprocesses include processes based on a nitrogen cycle, the APCI C3/MR™or Split MR™ or AP-X™ processes, the Phillips Optimized Cascade Process,the Linde Mixed Fluid Cascade process, the Shell Double MixedRefrigerant or Parallel Mixed Refrigerant process, or the AxensLIQUEFIN™ process.

In the embodiment illustrated in FIGS. 1 to 4, the LNG production plant10 includes a structure 28 in the form of a gravity based structurehaving a base 30 that rests on the seabed 32 at a selected location 34within the body of water 14, the gravity-based structure having a deck38 arranged above the level 40 of the water at the selected location 34.The selected location is offshore or near-shore. The shoreline isdesignated with the reference numeral 29.

By way of example, when the structure is in the form of a gravity basedstructure, the gravity based structure may be constructed usinglightweight or semi-lightweight concrete (having a density of less thanabout 2000 kg/m³). Alternatively or additionally, the gravity basedstructure may be constructed of steel or a hybrid comprising acombination of steel and concrete or a composite material.Advantageously, the gravity based structure is able to be constructedand commissioned at a construction location, such as a shipyard, where atrained and cost-efficient labour force is available and then floated into the first processing location 12 before being positioned at theselected location 34. Alternatively, the structure may be constructed inthe form of one or modules constructed on floated in barges orsubstructures with a topsides weight of up to 100,000 tons.

The structure 28 has a first cryogenic storage tank 42 operativelyassociated with the first phase liquefaction facility 24 for receivingLNG from the first phase liquefaction facility 24 and storing the firstphase product stream of LNG in the first cryogenic storage tank 42.Preferably, the first cryogenic storage tank 42 is one of a plurality offirst cryogenic storage tanks with two storage tanks shown in FIG. 3 byway of example only. The first cryogenic storage tank 42 may be a doublecontainment, full containment, prismatic or membrane systems with aprimary tank constructed from, by way of example, stainless steel,aluminum, and/or 9%-nickel steel. The first cryogenic storage tank mayinclude pre-tensioned concrete to provide structural resistance to thestored LNG, boil off gas pressure loads and to external hazards. Thestructure 28 further includes an LNG transfer facility 44 fortransferring LNG from the first cryogenic storage tank 42 to a secondcryogenic storage tank 46 onboard an LNG Carrier 48. Advantageously, thestructure 28 acts as a breakwater for the LNG Carrier 48 to reduceenvironmental loads on the LNG Carrier.

Referring to FIG. 5, the structure 28 is transportable from aconstruction location 50 to the first processing location 12 or from anassembly location 52 to the first processing location 12 by towing or onfloating barges. The construction location 50 may be one of a pluralityof constructions locations with three shown in FIG. 5 by way of exampleonly. Advantageously, testing or pre-commissioning of the structure 28can be conducted before transportation of the structure 28 to theprocessing location 14. This feature not only allows the structure to bedeployed where required but is also advantageous when maintenance orupgrading is required. The structure may be re-deployed at a differentlocation at a later time to suit LNG supply and demand, for example, dueto changes in the capacity of the LNG production plant or towards theend of a gas field life. Thus with reference to FIG. 5, the structurecan be moved from the first processing location 12 to a secondprocessing location 13.

Referring to FIG. 3, the first phase feed gas stream from theslugcatcher 20 is delivered to the gravity based structure 28 via asubsea pipeline 33. Referring to FIG. 4, the first phase feed gas streamfrom the slugcatcher 20 is delivered to the gravity based structure 28via a pipeline 35 arranged on a trestle 37. To allow sufficient waterdepth for an LNG Carrier 48 to berth alongside the gravity basedstructure 28, the selected location 34 has a water depth as measuredfrom the waterline 40 to the seabed 32 of between 15 and 50 meters.

When the structure 28 is in the form of a gravity based structure, thegravity based structure includes a ballast storage compartment 56,preferably arranged around the periphery of the gravity based structureor arranged toward the base of the gravity based structure, forballasting. For flexibility to adjust the level of ballasting to suitthe seabed conditions at a given selected location 34, the ballaststorage compartment 56 may be one of a plurality of ballast storagecompartments with four ballast storage compartments shown in FIGS. 1 and2, by way of example only. The gravity based structure 28 is towed fromthe construction or assembly location (50 or 52, respectively) to thefirst processing location 12 and then arranged at the selected location34 where settling is achieved by the addition of a ballasting materialto the ballast storage compartment 56 until the base 30 of the gravitybased structure 28 rests on the seabed 32 to secure the position of thegravity based structure 28. This provides the gravity based structurewith greater stability than a floating structure. The amount ofballasting material required to secure the gravity based structure tothe seabed at the selected location depends on a number of relevantfactors including but not limited to the shear strength of theunderlying clay or silt material found at the bottom of the body ofwater at the selected location. If required, the gravity based structure28 may include a piling system 58 to anchor the gravity based structure28 into the seabed 32. The ballasting material may be a solid ballastingmaterial or a liquid ballasting material. By way of example, one or bothof iron ore and sand may be used as the solid ballast material. In oneembodiment of the present invention, the liquid ballasting material iswater, condensate, monoethylene glycol (MEG), methanol, diesel,demineralised water, LPG or combinations thereof. The liquid ballastingmaterial may be stored in a non-cryogenic storage tank.

In this first embodiment of the present invention, the first phase LNGproduction plant 16 is provided for producing an initial plant capacityof LNG. The first phase LNG production plant 16 is provided with all ofthe equipment needed to produce the initial plant capacity of LNG withthe LNG so produced being stored in the first cryogenic storage tankonboard the structure 28. In use, an LNG Carrier 48 comes in to berth atthe structure 28 to receive a cargo of LNG. When the LNG Carrier isdocked at the structure 28 the first phase product stream of LNG 26 canbe directed into the second cryogenic storage tank 46 onboard the LNGCarrier. When there is no LNG Carrier docked at the gravity basedstructure 28, the first phase product stream of LNG 26 is directed tothe first cryogenic storage tank for storage onboard the gravity basedstructure 28.

The structure 28 is designed so that the LNG Carrier 48 may approach thestructure from either direction depending on the prevailing weatherconditions. A side of the structure that is sheltered from theprevailing weather conditions is referred to as the “lee side”.Preferably, the structure 28 has a lee side 60, whereby, in use, the LNGCarrier 48 approaches the structure 28 from the lee side 60. Thestructure 28 is designed and sized to have at least one lateral side 68which has a length of a sufficient size to allow an LNG carrier 48 to bedocked along alongside the structure 28 without overhang of any portionof the LNG Carrier 48 beyond an end 61 of the gravity based structure.The structure 28 can be fitted with fendering equipment (not shown) toabsorb a substantial portion of a load generated by any impact of theLNG Carrier 48 with the structure during transfer of LNG from the firstcryogenic tank 32 to the second cryogenic tank 46.

The first cryogenic storage tank 42 which is arranged below the deck ofthe structure 28 is operatively associated with the first phaseliquefaction facility 24 and receives a first phase product stream ofLNG 26 from the first phase liquefaction facility 24. The integrated LNGtransfer facility 44 located on the structure 28 includes a fixed orswivel joint loading arm or flexible hose above the water surface 40,preferably fitted with an emergency release system at one end of theloading arm or hose. Between transfer operations, the LNG transferfacility 44 may be kept cold by re-circulation of a small quantity ofLNG. The LNG transfer facility 44 may include an emergency safety systemto allow loading to be stopped if required in a quick, safe, andcontrolled manner by closing an isolation valve on the LNG transferlines or shutting down the cargo pumps associated with the secondcryogenic storage tank 46 onboard the LNG carrier 48. The emergencysafety system is designed to allow LNG transfer to be restarted withminimum delay after corrective action has been taken.

In a preferred embodiment, the structure 28 includes a boil-off gasreliquefaction facility 63 for liquefying at least a portion of the boiloff gas that is generated in first cryogenic storage tank 42 of thestructure 28 or during the transfer of the LNG from the first cryogenicstorage tank 42 to the second cryogenic storage tank 46 of the LNGCarrier 48. The reliquefied boil-off gas may be returned for storage inthe first cryogenic storage tank. Boil off gas is generated due to oneor more of the following: a) cooling down of the interior surfaces ofthe second cryogenic storage tank onboard the LNG Carrier; b) heatleaking in from the environment through the exterior surfaces of thesecond cryogenic storage tank onboard the LNG Carrier; c) heat from thecryogenic pumps used to transfer the LNG from the first cryogenicstorage tank to the second cryogenic storage tank; and d) heat ingressfrom the LNG transfer facility transfer hoses or loading arms; e)flashing off due to a temperature increase during the transferoperation, and, f) flashing due to pressure drop during LNG transferfrom liquefaction to storage. Alternatively or additionally, a portionof the boil off gas may be used as a source of fuel for a first phasepower generation system 62 arranged on the deck 38 of the structure 28.The first phase generation system 62 may be configured to provide powerto the first phase LNG liquefaction facility 24 as well as providingpower to other services and utilities of the structure 28, including theelectrical utility systems, the crew and cargo systems and associatedpumps, fans or other equipment associated with the liquefaction and gaspre-treatment facilities, the lighting systems, the accommodation unit,communications systems, inert gas and nitrogen generation systems, airsupply systems, water systems, and waste treatment.

The first phase LNG production plant 16 described above and illustratedin solid lines in FIG. 1 is provided, commissioned, and operated at aninitial plant capacity. Using the method and system of the presentinvention, the plant capacity of the first phase LNG production plant 16is expanded in one or more incremental stages by installing one or moresecond phase facilities to provide a second phase LNG production plant,said second phase LNG production plant having a maximum plant capacitythat is higher than the initial plant capacity. As can be seen from thearrangement of solid and dotted lines in FIG. 1, the first phase gaspre-treatment facility 22 and the first phase liquefaction facility 24are arranged towards a first end 70 of the structure 28 with apre-allocated space 71 being provided on the deck 32 of the structure 28in anticipation of the subsequent addition of one or more process unitsto provide a second phase gas pre-treatment facility 122 and a secondphase liquefaction facility 124. When installed, the second phase gaspre-treatment facility 122 and the second phase liquefaction facility124 are arranged towards a second opposite end 72 of the structure 28.In this way, it is possible to continue to process LNG in the firstphase LNG production plant 16 whilst undertaking the step of installingand commissioning the second phase LNG production plant 18 for expandingthe overall plant capacity from the initial plant capacity to a maximumplant capacity.

Referring to FIG. 2, after expansion, the second phase LNG productionplant 18 is arranged to receive a second phase hydrocarbon feed gasstream 123 from a second phase gas receiving facility 120 positionedonshore. In this embodiment, the second phase gas receiving facility 120is arranged to receive a second phase hydrocarbon stream 121 comprisinghydrocarbon gas and liquids and separating the liquids, including one orboth of condensate and free water, from the hydrocarbon stream toproduce the second phase hydrocarbon feed gas stream 123. In thisembodiment, after expansion, the LNG production plant 10 includes asecond phase offshore gas pre-treatment facility 122 for producing asecond phase stream of pre-treated gas 125, and a second phase offshoreliquefaction facility 124 for receiving the second phase stream ofpre-treated gas 125 from the second phase gas pre-treatment facility 122and liquefying the second phase pre-treated gas stream 125 to produce asecond phase product stream of LNG 126. Using the first embodiment ofthe present invention illustrated in FIGS. 1 and 2, when the secondphase product stream of LNG is combined with the first phase productstream of LNG, the overall plant capacity of the LNG production plant 10has been expanded from the initial plant capacity to a maximum plantcapacity in one incremental stage.

In the embodiment illustrated in FIGS. 1 to 4, the first cryogenicstorage tank 42 is operatively associated with both the first phase LNGproduction plant 16 and the second phase LNG production plant 18 andboth the first phase LNG product stream and the second phase LNG productstream are stored in the first cryogenic storage tank 42 or in one of aplurality of first cryogenic storage tanks. By way of example, thesecond cryogenic storage tank may have an LNG storage capacity in therange of 125,000 m³ to 260,000 m³. The first cryogenic storage tank 32has an LNG capacity of at least 160,000 m³. The upper limit of the LNGcapacity of the one or more first cryogenic storage tanks aboard thegravity based structure is around 400,000 m³ to 520,000 m³. The LNGtransfer facility 44 continues to perform the function of transferringLNG from the first cryogenic storage tank 42 to a second cryogenicstorage tank 46 onboard an LNG Carrier 48 when an LNG Carrier is dockedat the structure 28.

In use, after expansion, an LNG Carrier 48 comes in to berth at thestructure 28 to receive a cargo of LNG. When the LNG Carrier 48 isdocked at the structure 28 one or both of the first phase product streamof LNG 26 and the second phase product stream of LNG 126 may be directedinto one or more of the first cryogenic storage tank 42 of the gravitybased structure 28 or directed into the second cryogenic storage tank 46onboard the LNG Carrier 48 using the integrated transfer facilities 44.When there is no LNG Carrier docked at the structure 28, the first phaseproduct stream of LNG 26 and the second phase product stream of LNG 126are directed to the first cryogenic storage tank 42 for storage onboardthe structure 28.

In the first embodiment of the present invention illustrated withreference to FIGS. 1 to 4, the first cryogenic storage tank 42 or theplurality of first cryogenic storage tanks 42 is/are sized from theoutset to accommodate storage of LNG based on the maximum plant capacityof the LNG processing plant. In addition, the second phase LNGproduction plant 16 is provided with all of the equipment needed toproduce the second phase product stream of LNG 126 with the LNG soproduced being stored in the first cryogenic storage tank 42 onboard thegravity based structure 28. In order to accommodate expansion, thestructure is designed and sized to have a sufficient space on its deck38 to allow for installation of the one or more second phase facilitiesto provide the second phase LNG production plant 18. By way of example,the deck 38 of the structure may have a length of up to 370 meters and awidth of up to 150 meters. The depth of the structure may be up to 50metres.

A second embodiment of the present invention is now described withreference to FIGS. 6 and 7 for which like reference numerals refer tolike parts. As for FIGS. 1 and 2, the first phase LNG production plant16 is shown in solid lines in FIG. 6 and FIG. 7 whilst the second phaseLNG production plant 18 is shown in dotted lines in FIG. 6 with solidlines indicating that expansion has been completed in FIG. 7. The dottedlines in FIG. 6 represent the pre-allocated space 71 provided on thedeck 38 of the structure 28 for subsequent expansion. In this embodimentthe first phase gas receiving facility 20 is arranged on the deck 38 ofthe structure 28 with a pre-allocated space 71 being provided on thedeck 38 of the structure 28 in anticipation of the subsequent additionof the second phase gas receiving facility 120 to be installed at alater time when expansion of the plant capacity is desired. Thepre-allocated space 71 is arranged towards a first side 81 of thestructure 28 with the pre-allocated space being arranged towards asecond opposite side 83 of the structure.

A third embodiment of the present invention is now described withreference to FIGS. 8 to 10 for which like reference numerals refer tolike parts. As for FIGS. 1 and 2, the first phase LNG production plant16 is shown in solid lines in FIGS. 8 to 10 whilst the second phase LNGproduction plant 18 is shown in dotted lines. The dotted lines in FIGS.8 to 10 represent the pre-allocated space 71 provided on the deck 38 ofthe structure 28 for subsequent expansion. In this embodiment, the firstphase gas receiving facility 20 is designed and sized of sufficientcapacity to produce both the first phase hydrocarbon feed gas stream 23and the second phase hydrocarbon feed gas stream 123. In other words,the first phase gas receiving facility 20 is capable not only ofoperating at the initial plant capacity prior to expansion, but is alsocapable of operating at the maximum plant capacity after one or moreadditional units are added to provide the second phase production plant18. In FIG. 8, the first phase gas receiving facility 20 is arranged onthe deck 38 of the structure 28. In FIG. 9, the first phase gasreceiving facility 20 is arranged offshore or near-shore at a subsealocation 78. In FIG. 10, the first phase gas receiving facility 20 isarranged onshore. In each of the embodiments illustrated in FIGS. 8 to10, the first phase gas facility 20 is designed and sized to perform thefunction of both the first phase gas facility 20 and the second phasegas facility 120.

A fourth embodiment of the present invention is now described withreference to FIGS. 11 to 13 for which like reference numerals refer tolike parts. As for FIGS. 1 and 2, the first phase LNG production plant16 is shown in solid lines in FIGS. 11 to 13 whilst the second phase LNGproduction plant 18 is shown in dotted lines. The dotted lines in FIGS.11 to 13 represent the pre-allocated space 71 provided on the deck 38 ofthe 28 for subsequent expansion. In this embodiment, the first gaspre-treatment facility 22 is designed and sized of sufficient capacityto produce both the first phase pre-treated gas stream 25 and the secondphase pre-treated gas stream 125. In other words, the first phase gaspre-treatment facility 22 is capable not only of operating at theinitial plant capacity prior to expansion, but is also capable ofoperating at the maximum plant capacity after one or more additionalunits are added to provide the second phase production plant 18. In FIG.11, the first phase gas receiving facility 20 and the first phasepre-treatment facility 22 are arranged on the deck 38 of the structure28. Both are designed and sized to handle the maximum plant capacity butoperate at the initial plant capacity prior to expansion. In FIG. 12,the first phase gas receiving facility 20 and the first phasepre-treatment facility 22 are arranged onshore. As for FIG. 11, both aredesigned and sized to handle the maximum plant capacity but operate atthe initial plant capacity prior to expansion. In FIG. 13, the firstphase gas pre-treatment facility 22 is arranged on the structure 28 withthe first phase gas receiving facility 20 being arranged at a subsealocation 78. As for FIG. 11, both are designed and sized to handle themaximum plant capacity but operate at the initial plant capacity priorto expansion.

In each of the embodiments illustrated in FIGS. 1 to 4 and 6 to 13, theplant capacity of the first phase LNG processing plant is expanded inone incremental stage from the initial plant capacity to the maximumplant capacity. However, the plant capacity of the first phase LNGprocessing plant could equally be expanded in more incremental stagesfrom the initial plant capacity to the maximum plant capacity with threesuch incremental stages illustrated in the fifth embodiment nowdescribed with reference to FIGS. 14 to 17 for like reference numeralsrefer to like parts. As for FIGS. 1 and 2, the first phase LNGproduction plant 16 is shown in solid lines in FIG. 14 whilst each ofthe three incremental stages of the second phase LNG production plant 18are shown in dotted lines. It is to be understood that any number ofincremental stages may be added to the expandable LNG processing plantof the present invention to achieve the desired maximum plant capacity,with one and three incremental stages being shown in the figures anddescribed herein by way of example only. In the interests of clarity,the LNG Carrier is not shown in FIGS. 14 to 17. In FIG. 15, a firstincremental stage 80 has been added to the plant to increase the plantcapacity from the initial plant capacity of the first phase LNGprocessing plant to a first selected increased plant capacity. In FIG.16, a second incremental stage 82 has been added to the plant toincrease the plant capacity from the first selected increased plantcapacity to a second increased plant capacity. In FIG. 17, a third andfinal incremental stage 84 has been added to the plant to increase theplant capacity from the second selected increased plant capacity to themaximum plant capacity. As can be seen from the arrangement of solid anddotted lines in FIGS. 14 to 17, the first phase facilities 16 arearranged towards a first end 70 of the structure 28 with space 71 on thedeck 38 of the structure 28 pre-allocated for the installation ofadditional units for the first incremental stage 80, the secondincremental stage 82, and, the third and final incremental stage 84.

In a sixth embodiment, now described with reference to FIGS. 18 to 24,for which like reference numerals refer to like parts, three incrementalstages of expansion are illustrated as for FIGS. 14 to 17, by way ofexample only. The dotted lines in FIGS. 18 to 21 represent thepre-allocated space 71 provided on the deck 38 of the structure 28 forsubsequent expansion. In this embodiment, the first phase gas receivingfacility 20 is designed and sized to handle the initial plant capacityand each incremental increase in capacity up to the maximum plantcapacity. In the interests of clarity, the LNG Carrier is not shown inFIGS. 18 to 21. The first phase gas receiving facility 20 may be locatedonshore, subsea or on the deck of the structure. In this embodiment, theplant capacity of the first phase LNG production plant 16 is expanded inthree incremental stages by installing one or more second phasefacilities on the deck of the structure. In this embodiment, the one ormore second phase facilities take the form of one or more additional gaspre-treatment facilities 122, 222 and 322 in incremental stages toprovide a second phase LNG production plant, said second phase LNGproduction plant having a maximum plant capacity that is higher than theinitial plant capacity. It is apparent from FIGS. 18 to 21 that the deckof the structure is sized to provide sufficient room for installing theone or more additional gas pre-treatment facilities 122, 222 and 322 inthe pre-allocated space 71.

Depending on the demand for LNG, the final incremental stage may not berequired to be installed at the first processing location but may berequired to be installed at the second processing location or viceversa. In any event, sufficient pre-allocated space on the deck of thestructure is provided to allow expansion to occur with the first phaseLNG production plant arranged on the deck of the gravity based structurein a configuration that allows optimum access for later installation ofadditional units.

In the sixth embodiment illustrated in FIGS. 18 to 21, one or moreadditional LNG liquefaction facilities 124, 224 and 324 are also addedin incremental stages in sequence with the one or more additional gaspre-treatment facilities 122, 222 and 322 to provide the second phaseLNG production plant 18. As best seen in FIGS. 22 and 23, the one ormore additional LNG liquefaction facilities 124, 224 and 324 are locatedon a fixed platform, a semi-submersible platform (such as a tension-legplatform or a “SPAR”) or a “jacket” structure. This embodiment has anumber of advantages. Firstly, it allows for the liquefaction facilitiesto be installed as modules of up to 100,000 tons in weight which ishigher than the maximum size of module that can be installed onshorebecause these modules can be floated in and installed on the fixedstructure, avoiding the limitations to size associated with heavylifting for installation at an onshore facility. Onshore moduleinstallations are limited in size by the available crane capacity,limiting the highest possible size of an onshore module to around 7,000tons. Secondly, it allows for the liquefaction facilities to be locatedat a safe working distance away from the gravity based structure whichis particularly advantageous if the liquefaction facilities rely onpropane for cooling as part of the liquefaction process. Power issupplied to the liquefaction modules from the first phase powergeneration facility 62 onboard the structure 28 via a subsea power cablewith the compressors and liquefaction equipment being driven by electricmotors. As each of the one or more additional LNG liquefactionfacilities 124, 224 and 324 are added during expansion, one or moreadditional second phase power generation facilities (not shown) can beinstalled on the deck of the gravity based structure. This allows for amore compact design of the one or more additional LNG liquefactionfacilities 124, 224 and 324. Alternatively, as illustrated in FIGS. 18to 21, the first phase power generation facilities 62 can be designedand sized to meet the anticipated power demands of the expandable LNGprocessing plant when it is operating at both the initial plant capacityand the maximum plant capacity.

Using any of the embodiments described above, structure 28 may includeone or both of a condensate storage tank and an LPG storage tank. By wayof example, the condensate storage tank may be up to 130,000 m³ in sizewith the LPG storage tank being up to 90,000 m³ in size. Suitable marinevessels can berth at the gravity based structure for offloading of oneor both of the condensate or LPG as desired.

The embodiments described above were all in the context of the LNGprocessing plant being used for LNG liquefaction. When the LNGprocessing plant is used for LNG regasification, the present inventionprovides a system and method of vaporising LNG in an LNG regasificationplant positioned at a processing location adjacent to a body of water.The method comprises:

-   -   A) providing a first phase LNG regasification plant for        vaporising an initial plant capacity of LNG, the first phase LNG        regasification plant comprising a plurality of spaced-apart        first phase facilities, each first phase facility provided with        plant equipment related to a pre-determined function associated        with the regasification of LNG, wherein one or more of the        plurality of spaced-apart first phase facilities is arranged on        a gravity based structure having a base that rests on the seabed        at a selected location within the body of water, the gravity        based structure having a deck arranged above the level of the        water at an offshore or near-shore selected location; and,    -   B) expanding the plant capacity of the first phase LNG        regasification plant in one or more incremental stages by        providing one or more second phase facilities on the deck of the        gravity based structure to provide a second phase LNG        regasification plant, said second phase LNG regasification plant        having a maximum plant capacity that is higher than the initial        plant capacity.

In order to facilitate expansion, the deck of the structure is designedand sized to provide a pre-allocated space on the deck for theinstallation of the one or more second phase facilities on the deck inan analogous manner to the embodiments described above for an LNGliquefaction plant. Advantageously, regasification of LNG from the firstphase LNG regasification plant is able to continue during the step ofexpansion. The first phase LNG regasification plant is arranged on thedeck of the gravity based structure in such a way as to provide easyaccess to the pre-allocated space.

Any of the embodiments illustrated in FIGS. 1 to 23 and described abovein the context of the LNG processing plant being an LNG liquefactionplant could equally be modified for use an as LNG regasification plantby way of the following substitutions:

-   -   a) the first phase gas receiving facility is replaced with a        first phase power generation facility 20 for generating a supply        of power 21 using a first phase product stream of natural gas 23        as a source of fuel to generate electricity;    -   b) the second phase gas receiving facility is replaced with a        second phase power generation facility 120 for generating        electricity using a second phase stream of natural gas as a        source of fuel (designed by reference numeral 123);    -   c) the first phase gas pre-treatment facility is replaced by a        first phase vaporised gas receiving facility 22 arranged to        receive a stream of vaporised natural gas 25 from a first phase        regasification facility 24 and send out a first phase product        stream of vaporised natural gas 25;    -   d) the second phase gas pre-treatment facility is replaced by a        second phase vaporised gas receiving facility 122 arranged to        receive a stream of vaporised natural gas from the second phase        regasification facility 124 and send out a second phase product        stream of vaporised natural gas 125;    -   e) the first phase liquefaction facility is replaced by the        first phase regasification facility 24 arranged to vaporise a        first phase feed stream of LNG 26 to produce the first phase        stream of vaporised natural gas 25 which is transferred to the        first phase vaporised gas receiving facility 22; and,    -   f) the second phase liquefaction facility is replaced by a        second phase regasification facility 124 arranged to vaporise a        second phase feed stream of LNG 126 to produce the second phase        stream of vaporised natural gas 125 delivered to the second        phase vaporised gas receiving facility 122.

The first cryogenic storage tank 42 of the structure 28 is used to storeLNG for the LNG regasification plant in the same manner as it was usedto store LNG for the LNG liquefaction plant. When used forregasification, the LNG transfer facilities 44 are used to transfer LNGfrom a second cryogenic storage tank 46 onboard an LNG Carrier 48 to thefirst storage tank 42 of the structure 28.

A seventh embodiment of the present invention is now described in detailwith reference to the embodiment illustrated in FIGS. 1 and 2 in thecontext of the LNG processing plant being an LNG regasification plant,with like reference numerals referring to like parts or thesubstitutions set out above. Referring to FIGS. 1 to 4, an LNGprocessing plant 10, in the form of an LNG regasification plant, ispositioned at a first processing location 12 adjacent to a body of water14. The LNG regasification plant 10 includes a first phase LNGregasification plant 16 for producing an initial plant capacity of LNGillustrated in solid lines in both FIG. 1 and FIG. 2, with apre-allocated space 71 provided on the deck 38 of the structure 28 forthe later expansion of the LNG processing plant 10 in one or moreincremental stages to provide a second phase LNG regasification plant18, said second phase LNG regasification plant having a maximum plantcapacity that is higher than the initial plant capacity. The secondphase LNG regasification plant 18 is illustrated in dotted lines in FIG.1 and solid lines in FIG. 2. In the first embodiment illustrated inFIGS. 1 and 2, the plant capacity of the first phase LNG regasificationplant 16 is increased in one incremental stage by installing one or moresecond phase facilities to provide the second phase LNG regasificationplant. This expansion is able to be conducted without interruption tothe processing of LNG by the first phase LNG regasification plant.

In the first embodiment now described with reference to FIGS. 1 to 4,the first phase LNG regasification plant 16 includes first phase powergeneration facility 20 for generating electricity using natural gas as asource of fuel. The LNG production plant 10 includes a first phasevaporised gas receiving facility 22 arranged to receive a stream ofvaporised natural gas 25 from a first phase regasification facility 24.In this embodiment, the first phase LNG regasification plant 16 includesa first phase regasification facility 24 arranged to vaporise a firstphase feed stream of LNG 26 to produce the first phase stream ofvaporised natural gas 25 which is transferred to the first phasevaporised gas receiving facility 22. The first phase feed stream of LNGis vaporised at a rate that is determined by the initial plant capacityof LNG of the first phase LNG regasification plant 16. The initial plantcapacity of the first phase LNG regasification plant 16 is in the rangeof 0.5 to 7 million tons per annum of LNG. The maximum plant capacityafter expansion to provide the second phase LNG regasification plant 18is in the range of 2 million to 20 million tons per annum of LNG.

Vaporisation of the LNG is achieved in the first phase regasificationfacility 24 using any regasification process well established in theart. Such prior art regasification processes include use a variety ofsources of heat for vaporization of LNG. However, the use of forced ornatural draft ambient air as a primary source of heat for vaporizationof LNG is preferred to keep emissions to a minimum compared with otherregasification technologies that rely on the use of seawater or theburning of liquid fuels as the primary heat source for vaporization.

In the embodiment illustrated in FIGS. 1 to 4, the LNG regasificationplant 10 includes a gravity based structure having a base 30 that restson the seabed 32 at a selected location 34 within the body of water 36,the gravity based structure having a deck 38 arranged above the level 40of the water at the selected location. The selected location is offshoreor near-shore. The gravity based structure 28 has a first cryogenicstorage tank 42 for storage of LNG. The first cryogenic storage tank 42is preferably one of a plurality of first cryogenic storage tanks withonly one shown in the figures in the interests of clarity. The gravitybased structure 28 further includes an LNG transfer facility 44 fortransferring LNG from a second cryogenic storage tank 46 onboard an LNGCarrier 48 to the first cryogenic storage tank 42. LNG from the firstcryogenic storage tank is delivered as a first phase feed stream to thefirst phase regasification facility 24 for vaporisation.

Referring to FIG. 3, the first phase product stream of natural gas 23 isdelivered from the gravity based structure 28 to the first phase powerplant 20 via a subsea pipeline 33. Referring to FIG. 4, the first phaseproduct stream of natural gas 23 is delivered from the gravity basedstructure 28 to the first phase power plant 20 via a pipeline 35arranged on a trestle 37.

In this first embodiment of the present invention, the first phase LNGregasification plant 16 is provided for vaporising an initial plantcapacity of LNG. The first phase LNG regasification plant 16 is providedwith all of the equipment needed to vaporise the initial plant capacityof LNG with the LNG being stored in the first cryogenic storage tankonboard the gravity based structure. In use, an LNG Carrier 48 comes into berth at the gravity based structure 28 to deliver a cargo of LNG.When the LNG Carrier is docked at the gravity based structure 28 thefirst phase feed stream of LNG 26 is offloaded from the second cryogenicstorage tank 46 onboard the LNG Carrier 48 into one or more of the firstcryogenic storage tanks 42 of the gravity based structure. When there isno LNG Carrier docked at the gravity based structure 28, the first phasefeed stream of LNG 26 is sourced from the LNG stored in a firstcryogenic storage tank 42 of the gravity based structure 28. Given thelarge capacity of the first cryogenic storage tank 42, this allows forthe first phase power plant 20 to be provided with a continuous sourceof natural gas a fuel to generate electricity in between cargodeliveries from an LNG Carrier.

The first phase LNG regasification plant 16 described above andillustrated in solid lines in FIG. 1 is provided, commissioned, andoperated at an initial plant capacity. Using the method and system ofthe present invention, the plant capacity of the first phase LNGregasification plant 16 is expanded in one or more incremental stages byinstalling one or more second phase facilities to provide a second phaseLNG regasification plant 18, said second phase LNG regasification planthaving a maximum plant capacity that is higher than the initial plantcapacity. As can be seen from the arrangement of solid and dotted linesin FIG. 1, the first phase vaporised gas receiving facility 22 and thefirst phase regasification facility 24 are arranged towards a first end70 of the structure 28 with a pre-allocated space 71 being provided onthe deck 32 of the structure 28 in anticipation of the subsequentaddition of one or more process units to provide the second phase gasvaporised gas receiving facility 122 and the second phase regasificationfacility 124. When installed, the second phase vaporised gas receivingfacility 122 and the second phase regasification facility 124 arearranged towards a second opposite end 72 of the structure 28. In thisway, it is possible to continue to vaporise LNG in the first phase LNGregasification plant 16 whilst undertaking the step of installing andcommissioning the second phase LNG regasification plant 18 for expandingthe overall plant capacity from the plant capacity to a maximum plantcapacity.

Referring to FIG. 2, after expansion, the second phase LNGregasification plant 18 is arranged to produce a second phase naturalgas product stream 123 to act as a source of fuel to a second phasepower generation facility 120 positioned onshore. Using the firstembodiment of the present invention illustrated in FIGS. 1 and 2, whenthe second phase feed stream of LNG 126 is combined with the first phasefeed stream of LNG 26, the overall plant capacity of the LNGregasification plant 10 has been expanded from the initial plantcapacity to a maximum plant capacity in one incremental stage. Thenumber and arrangement of gas turbines used in the first powergeneration facility 20 and the second phase power generation facility120 depends on the capacity of LNG regasification facility. Using thisembodiment of the present invention, the first phase power generationfacility 20 operates on the basis of the initial capacity of the firstphase LNG regasification plant and is subsequently expanded to themaximum capacity of the second phase LNG regasification plant.

In an analogous manner, the second to sixth embodiments described indetail above can be applied to the vaporisation of LNG using thesubstitutions described above to change the LNG processing plant from aliquefaction plant to a regasification plant.

Using any of the LNG regasification embodiments illustrated in FIGS. 1to 23, the first phase power generation facility 20 and the second phasepower generation facility 120 use a product stream of natural gas (23and 123, respectively) as a source of fuel for generating electricity.By way of example, the power generation facility 20 includes one or moregas-fired power generation units, in this example a gas turbine arrangedto use unodorized natural gas that has been vaporized from LNG stored inthe first cryogenic storage tank as a source of fuel gas. Natural gaswhich is generated during vaporization of LNG is “unodorized” in thatsulfur compounds are removed from well head gas prior to liquefaction.In contrast, pipeline natural gas sourced from an onshore gasdistribution facility includes a sulfur containing odorant which isdeliberately added to gas intended for use by consumers prior todistribution for the purpose of facilitating detection of leaks. The useof “unodorized” vaporized LNG leads to a reduction in the level ofsulfur dioxide produced in the exhaust gas from the gas turbine of thepresent invention. LNG also does not contain heavy hydrocarbons (whichhave been removed during gas conditioning prior to liquefaction) andthis leads to reduction in the particulates present in the exhaust gasproduced by the gas turbine of the present invention compared with a gasturbine operated using odorized natural gas from an onshore gasdistribution facility. The unodorized natural gas is used as one of thesources of fuel for the gas turbines of the power generation facility isderived from one or more of the following sources: a) natural boil offgas from the first cryogenic storage tank; b) forced boil off gas fromthe first cryogenic storage tank; and, c) LNG vaporized to natural gasusing the first or second phase regasification facilities.

Each gas turbine produces energy by combustion of a source of fuel gasmixed with intake air from an air compressor. The hot combustion gasesare directed to flow across the blades (not shown) of the gas turbine,causing the turbine to spin providing rotation to a mechanical shaft todrive a first generator. Additional thrust can be provided byacceleration of the combustion gases through a nozzle. During combustionof any fuel gas, pollutants are produced which report to the exhaustgas. The quantity and type of pollutant produced in the exhaust gasdepends on such relevant factors as the efficiency of combustion, thedegree of air compression, the air-to-fuel ratio, the inlet temperatureof the compressed air and the fuel gas, the humidity of the inlet air,ignition timing, efficiency of combustion and the type of fuel gassupplied to the gas turbine. Advantageously, the power generationfacility of the present invention uses unodorized natural gas that hasbeen vaporized from LNG as the source of fuel gas, which produces alower level of emissions and pollutants than would be produced byburning oil or coal to fire the burners of a traditional prior art steamturbine.

A fuel gas conditioning unit can be provided with temperature regulatorfor measuring and adjusting the temperature of the vaporized gas, asrequired, to improve the combustion efficiency of the gas turbine. Heatis supplied to the temperature regulator using electrical heating, steamheating, or by circulating a warm intermediate fluid.

It is readily apparent from the embodiments illustrated in FIGS. 1 to 23that the first power generation facility 20 may be located onshore,offshore on the deck of the gravity based structure or near shore as aseparate facility. The first phase power generation facility 20 may bean existing onshore power generation facility or purpose-built as one ofthe plurality of facilities of the first phase LNG regasification plant16.

Whilst the various embodiments have been described above in the contextof the structure 28 being a gravity based structure, the structure 28may be in the form of a floating structure as illustrated by way ofexample only in FIG. 22, provided only that the deck of the structure issized to provide a pre-allocated space for the installation of the oneor more second phase facilities on the deck of the structure tofacilitate expansion of the plant capacity of the first phase LNGprocessing plant in one or more incremental stages to form the secondphase LNG processing plant. Alternatively, the structure may be a fixedplatform, a semi-submersible platform (such as a tension-leg platform ora “SPAR”) or a “jacket” structure as illustrated, by way of exampleonly, in FIG. 23, provided that the deck of the structure is sized toprovide a pre-allocated space for the installation of the one or moresecond phase facilities on the deck of the structure to facilitateexpansion of the plant capacity of the first phase LNG processing plantin one or more incremental stages to form the second phase LNGprocessing plant.

Various embodiments of the present invention provide at least thefollowing advantages over the prior art:

-   -   a) expansion of the capacity of the first phase processing plant        the second phase processing plant is made possible using larger        process units than those able to be accommodated during the        expansion of an onshore processing plant. When conducting        expansion operations onshore, the size of the modules that can        be mobilized using cranes and land-based transport vehicles are        limited to around 2500 to 7000 tons. In contrast, using the        present invention, process units and modules of 30,000 to 40,000        tons and up to 100,000 tons can be floated in without ever        needing to be lifted or transported on land.    -   b) sizing the first cryogenic storage tank onboard the structure        to accommodate the initial plant capacity and the maximum plant        capacity allows for the addition of second phase liquefaction        facilities which do not require any LNG storage of their own.        The result of this is that the size of the second phase        liquefaction facilities can be larger than possible to achieve        onshore.    -   c) the present invention provides an offshore LNG production        option that is expandable in terms of capacity which is not        possible using prior art ‘floating LNG’ options which rely on        the deck space being fully occupied with processing equipment.    -   d) the costs associated with the dredging and construction of        port facilities to provide a jetty for berthing of LNG Carriers        is avoided as the fixed or floating structure of the present        invention provides berthing facilities and serves as a        breakwater for LNG Carriers.    -   e) the structure can be manufactured in a shipyard and then        floated in to the first processing location, which greatly        reduces costs compared to in situ construction of a long jetty        and breakwater reducing the cost of construction and        installation.    -   f) In addition when the structure is a gravity based structure,        the gravity based structure can be de-ballasted, transported        from the first processing location to a second processing        location, and re-ballasted at the second processing location,        avoiding the costs associated with in situ construction of a        jetty and breakwater at both the first processing location and        the second processing location.    -   g) The structure can be used as a liquefaction plant, a        regasification plant, or an offshore or near shore power        station, whereby the capital costs are lower than the costs of a        separate land based liquefaction plant, regasification plant or        power station.    -   h) The structure can be provided with a first cryogenic storage        tank with an extremely large storage capability which enables        continuous operation of the LNG processing plants even though        deliveries to or from LNG Carriers are made intermittently and,        even more importantly, can be sized to accommodate the largest        supertankers.    -   i) Using the present invention results in substantial savings in        the overall operation of the process at maximum capacity and        provides for great ease in expanding the process incrementally.

Now that several embodiments of the invention have been described indetail, it will be apparent to persons skilled in the relevant art thatnumerous variations and modifications can be made without departing fromthe basic inventive concepts. All such modifications and variations areconsidered to be within the scope of the present invention, the natureof which is to be determined from the foregoing description and theappended claims.

It will be clearly understood that, although a number of prior artpublications are referred to herein, this reference does not constitutean admission that any of these documents forms part of the commongeneral knowledge in the art, in Australia or in any other country. Inthe summary of the invention, the description and claims which follow,except where the context requires otherwise due to express language ornecessary implication, the word “comprise” or variations such as“comprises” or “comprising” is used in an inclusive sense, i.e. tospecify the presence of the stated features but not to preclude thepresence or addition of further features in various embodiments of theinvention.

1. An LNG processing plant positioned at a processing location adjacentto a body of water, the LNG processing plant comprising: A) a firstphase LNG processing plant for processing an initial plant capacity ofLNG, the first phase LNG processing plant comprising a plurality offirst phase facilities, each first phase facility provided with plantequipment related to a pre-determined function associated with theprocessing of LNG, wherein one or more of the plurality of first phasefacilities is arranged on a deck of a structure wherein the deck isarranged above the level of the water at a selected offshore ornear-shore location; and, B) one or more second phase facilitiesprovided on the deck of the structure to provide a second phase LNGprocessing plant, said second phase LNG processing plant having amaximum plant capacity that is higher than the initial plant capacity,wherein the one or more second phase facilities are provided to expandthe plant capacity of the first phase LNG processing plant in one ormore incremental stages, and, the deck of the structure is sized toprovide a pre-allocated space for the installation of the one or moresecond phase facilities on the deck of the structure.
 2. The LNGprocessing plant of claim 1 wherein the one or more of the plurality offirst phase facilities is arranged towards: (a) a first end of the deckwith the pre-allocated space being arranged towards a second oppositeend of the deck; or (b) a first side of the deck with the pre-allocatedspace being arranged towards a second opposite side of the deck. 3.(canceled)
 4. The LNG processing plant of claim 1 wherein the structureis a fixed structure or a floating structure or a gravity basedstructure having a base that rests on the seabed at the selectedlocation.
 5. The LNG processing plant of claim 1 wherein the structureincludes a first cryogenic storage tank for receiving and storing LNG.6. The LNG processing plant of claim 5 wherein the first cryogenicstorage tank is either: (a) a prismatic storage tank; (b) a membranestorage tank; or (c) one of a plurality of first cryogenic storagetanks. 7-11. (canceled)
 12. The LNG processing plant of claim 1 whereinthe plant has one or both of (a) initial plant capacity of the firstphase LNG processing plant is in the range of 0.5 to 7 million tons perannum of LNG; and (b) a maximum capacity after expansion to provide thesecond phase LNG processing plant in the range of 2 million to 50million tons per annum of LNG.
 13. (canceled)
 14. The LNG processingplant of claim 1 wherein one or more of the plurality of first phasefacilities is sized for processing both the initial plant capacity andthe maximum plant capacity.
 15. The LNG processing plant of claim 1wherein one or more of second phase facilities is located on a fixedplatform, a semi-submersible or a jacket structure. 16-17. (canceled)18. The LNG processing plant of claim 4 wherein the gravity structureincludes one or both of a condensate storage tank and an LPG storagetank.
 19. The LNG processing plant of claim 1 wherein the structureincludes an LNG transfer facility for loading LNG between from the firstcryogenic storage tank of the structure to a second cryogenic storagetank onboard an LNG Carrier, or for unloading of LNG from the secondcryogenic storage tank of an LNG Carrier to the first cryogenic storagetank of the structure.
 20. (canceled)
 21. The LNG processing plant ofclaim 1 wherein the structure is arranged to provide a breakwater for anLNG Carrier at the selected location.
 22. The LNG processing plant ofany one of the preceding claims wherein the structure is transportablefrom a first processing location to a second processing location. 23.The LNG processing plant of claim 1 wherein the structure is a gravitybased structure and the gravity based structure includes a at least oneballast storage compartment arranged around the periphery of the gravitybased structure or arranged toward the base of the gravity basedstructure, for ballasting.
 24. (canceled)
 25. The LNG processing plantof claim 1 wherein the LNG processing plant is an LNG production plantarranged to receive a feed stream of natural gas and liquefy the naturalgas to produce a product stream of LNG.
 26. The LNG processing plant ofclaim 25 wherein the first phase LNG processing plant includes a firstphase gas receiving facility for receiving a hydrocarbon streamcomprising hydrocarbon gas and liquids and separating the liquids,including one or both of condensate and free water, from the hydrocarbonstream to produce a hydrocarbon feed gas stream for a gas pre-treatmentfacility.
 27. The LNG processing plant of claim 26 wherein the firstphase gas receiving facility is arranged (a) on the deck of thestructure; or (b) offshore; or (c) subsea; or (d) onshore. 28-29.(canceled)
 30. The LNG processing plant of claim 25 wherein the firstphase LNG processing plant includes a first phase gas pre-treatmentfacility for receiving a hydrocarbon feed gas stream from a gasreceiving facility and removing contaminants from the hydrocarbon feedgas stream to produce a stream of pre-treated gas.
 31. The LNGprocessing plant of claim 30 wherein the first phase gas pre-treatmentfacility is arranged (a) on the deck of the structure; or (b) onshore;or (c) offshore. 32-33. (canceled)
 34. The LNG processing plant of claim25 wherein the first phase LNG processing plant includes a first phaseLNG liquefaction facility for receiving the stream of pre-treated gasfrom a gas pre-treatment facility and liquefying the natural gas toproduce a product stream of LNG.
 35. The LNG processing plant of claim34 wherein the first phase LNG liquefaction facility is arranged (a) onthe deck of the structure; or (b) onshore; or (c) offshore. 36-37.(canceled)
 38. The LNG processing plant of claim 25 wherein thestructure includes a boil-off gas reliquefaction facility for liquefyingat least a portion of the boil off gas that is generated in firstcryogenic storage tank.
 39. The LNG processing plant of claim 1 whereinthe LNG processing plant is an LNG regasification plant arranged toreceive a feed stream of LNG and vaporise the LNG to produce a productstream of natural gas.
 40. The LNG processing plant of claim 39 whereinthe first phase LNG regasification plant includes a first phase powergeneration facility for generating a supply of power using a first phaseproduct stream of natural gas as a source of fuel to generateelectricity.
 41. The LNG processing plant of claim 40 wherein the firstphase power generation facility is (a) arranged on the deck of thestructure; or (b) arranged onshore; or (c) arranged offshore; or (d) apre-existing onshore power plant. 42-44. (canceled)
 45. The LNGprocessing plant of claim 39 wherein the first phase LNG regasificationplant includes a first phase vaporised gas receiving facility arrangedto receive a stream of vaporised natural gas from a first phaseregasification facility and send out a first phase product stream ofvaporised natural gas.
 46. The LNG processing plant of claim 45 whereinthe first phase vaporised gas receiving facility is arranged (a) on thedeck of the structure; (b) onshore; or (c) offshore. 47-48. (canceled)49. The LNG processing plant of claim 39 wherein the first phase LNGregasification plant includes a first phase regasification facilityarranged to vaporise a first phase feed stream of LNG to produce a firstphase stream of vaporised natural gas which is transferred to a firstphase vaporised gas receiving facility.
 50. The LNG processing plant ofclaim 49 wherein the first phase regasification facility is arranged (a)on the deck of the structure; or (b) onshore; or (c) offshore. 51-52.(canceled)
 53. The LNG processing plant of claim 1 wherein the initialplant capacity is at least 0.5 million tons per year and the maximumfeed processing capacity is at least 2 million tons per year.
 54. TheLNG processing plant of claim 1 wherein the first initial plant capacityis (a) at least 0.5 million tons per year and the maximum feedprocessing capacity is not greater than 50 million tons per year; or (b)at least 0.5 million tons per year and the maximum feed processingcapacity is not greater than 70 million tons per year.
 55. (canceled)56. A method of processing LNG in an LNG processing plant is positionedat a processing location adjacent to a body of water, the methodcomprising: A) providing a first phase LNG processing plant forprocessing an initial plant capacity of LNG, the first phase LNGprocessing plant comprising a plurality of first phase facilities, eachfirst phase facility having plant equipment related to a pre-determinedfunction associated with the processing of LNG, wherein one or more ofthe plurality of first phase facilities is arranged on a deck of astructure, wherein the deck is arranged above the level of the water ata selected offshore or near-shore location; and, B) expanding the plantcapacity of the first phase LNG processing plant in one or moreincremental stages by providing one or more second phase facilities onthe deck of the structure to provide a second phase LNG processingplant, said second phase LNG processing plant having a maximum plantcapacity that is higher than the initial plant capacity, wherein thedeck of the structure is sized to provide a pre-allocated space for theinstallation of the one or more second phase facilities on the deck ofthe structure.
 57. The method of claim 56 comprising the step ofprocessing LNG from the first phase LNG processing plant during step B).58. The method of claim 56 comprising the step of (a) arranging the oneor more of the plurality of first phase facilities towards a first endof the deck with the pre-allocated space being arranged towards a secondopposite end of the deck; or (b) the one or more of the plurality offirst phase facilities towards a first side of the deck with thepre-allocated space being arranged towards a second opposite side ofdeck. 59-61. (canceled)
 62. The method of claim 56 comprising the stepof sizing the one or more of the plurality of first phase facilities forprocessing both the initial plant capacity and the maximum plantcapacity. 63-66. (canceled)
 67. The method of claim 56 comprising thestep of arranging the structure to provide a breakwater for an LNGCarrier at the selected location.
 68. The method of claim 56 comprisingthe step of moving the structure from a first processing location to asecond processing location.
 69. The method of claim 56 wherein the LNGprocessing plant is an LNG production plant arranged to receive a feedstream of natural gas and liquefy the natural gas to produce a productstream of LNG.
 70. The method of claim 56 wherein the LNG processingplant is an LNG regasification plant arranged to receive a feed streamof LNG and vaporise the LNG to produce a product stream of natural gas.71-72. (canceled)